Rear projector

ABSTRACT

In order to provide a rear projector capable of facilitating position adjustment of an image displayed on a screen and optimizing dispersion of the aspect ratio of the projected image caused by tolerance of components by adjusting the position of the image, a support member ( 200 ) is provided with a lateral position adjuster ( 202 ) as a planar position adjusting mechanism attached on a support plate of an interior unit in an opposing manner, an inclination adjuster ( 203 ) as an inclination position adjusting mechanism vertically provided on the lateral position adjuster ( 202 ), and a rotary position adjuster ( 204 ) as a rotary position adjusting mechanism attached to the inclination adjuster ( 203 ) slanted downward toward rear side.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a rear projector that displaysimage on a transmissive screen.

[0003] 2. Description of Related Art

[0004] Conventionally, a rear projector that displays a projected andenlarged image on a screen is known as a large-screen display device.

[0005] In such rear projector, the light beam from a light source isirradiated on a transmissive liquid crystal panel, where the light beamis modulated in accordance with image information by the transmissiveliquid crystal panel, and is enlarged by a projection lens, of whichoptical path is changed by a reflection mirror to be introduced to arear side of a screen.

[0006] According to the above arrangement, all of the components can behoused in a movable casing and the image on the screen can be viewed ina well-lighted room.

[0007] In order to adjust the position of the image displayed on thescreen, a position adjuster, which normally adjusts the position of theprojection lens in horizontal or vertical position, is necessary forsuch rear projector. Such mechanism is shown in, for instance, JapanesePatent Laid-Open Publication No. 2001-94905 and Japanese PatentLaid-Open Publication No. 2002-107663.

[0008] However, when such simple position adjuster where the position ofthe projection lens is horizontally or vertically adjusted is used foradjusting the position of the image, there is certain limit capable ofadjusting the display position of the image and undisplayable area fordisplaying the image is formed on the screen even after adjusting theposition of the projection lens.

[0009] Further, there is difference in the tolerance of the profile ofthe casing of the rear projector and the tolerance of the componentinstalled in the casing, the tolerance causing difference in aspectratio of the displayed image, so that the projection dispersion isgenerated on the image displayed on the screen.

[0010] Minute adjustment is required to optimize the projectiondispersion. However, since undisplayable area is formed by theconventional divisional display position adjuster, the image cannot bedisplayed on the entire screen and, when large undisplayable area isformed, the displayed image runs off the edge of the screen and only theimage displayed within the frame of the screen can be recognized by aviewer.

SUMMARY OF THE INVENTION

[0011] An object of the present invention is to provide a rear projectorcapable of facilitating the position adjustment of the image displayedon the screen and optimizing the projection dispersion of the aspectratio of the image caused by tolerance of components.

[0012] A rear projector according to an aspect of the present inventioncomprises: an image generator having an electric optical device thatmodulates a light beam irradiated by a light source and forms an opticalimage in accordance with image information and a projection opticalsystem that enlarges and projects the optical image; a box-shaped casingthat houses the image generator; and a screen exposed on one of thelateral sides of the box-shaped casing onto which the optical imagegenerated by the image generator is projected, the casing having asupport plate that supports the image generator, the image generatorbeing mounted on a support base having a support surface inclinedrelative to the support plate, the support plate being provided with aninclination position adjusting mechanism that adjusts the inclinationposition of the image generator relative to the support plate.

[0013] The support plate may be a component independent of the casing,or may be one of the upper side, lateral side or lower side of thecasing.

[0014] In the above aspect of the present invention, the support plateis provided on the casing and the image generator is located on thesupport base having a support surface slanted relative to the supportplate, where the inclination position adjusting mechanism is provided onthe support base. The attitude of the image generator projecting thegenerated optical image is adjusted by the inclination positionadjusting mechanism. Accordingly, distortion of the image displayed onthe screen can be optimized by adjusting the attitude thereof and theundisplayable area of the image projected on the screen can be narrowedin adjusting the position of the image projected and displayed on thescreen by the image generator. Accordingly, even when the aspect ratioof the displayed image changes according to difference in tolerance ofthe configuration of the casing of the rear projector and tolerance ofthe components installed in the casing and dispersion is caused on theimage displayed on the screen, optimization is possible by adjusting theattitude of the image generator by the inclination position adjustingmechanism, thus displaying the image on the entire screen.

[0015] Further, since the image generator is disposed on the supportbase having the support surface inclined relative to the support plate,the dimension of the rear projector in a direction to be away from thescreen, i.e. the thickness of the rear projector can be reduced, thusreducing the size of the projector.

[0016] In the rear projector according to an aspect of the presentinvention, the support base may preferably be disposed on the supportplate in an inclined manner.

[0017] According to the above arrangement, self-weight of the imagegenerator can be securely received by the support base and the supportplate, thus securely supporting the image generator in accordance withattitude adjustment of the image generator.

[0018] In the rear projector according to an aspect of the presentinvention, the support base may preferably be disposed on the lower sideof the support plate in an inclined manner.

[0019] According to the above arrangement, the image generator islocated between the support plate and the support base and is isolatedin the casing from the other components such as the screen. Therefore,even when heat is generated in the image generator, heat migration tothe other components such as the screen can be prevented by circulatingcooling air along the support plate and the support base.

[0020] In the rear projector according to an aspect of the presentinvention, a planar position adjusting mechanism that adjusts the planarposition of the image generator relative to the screen may preferably beprovided on the support base.

[0021] According to the above arrangement, the planar position of theimage generator relative to the screen surface can be adjusted byproviding the planar position adjusting mechanism on the support base,so that the focus or the display position of the image displayed on thescreen can be adjusted.

[0022] Accordingly, even when the aspect ratio of the displayed image ischanged on account of difference in the tolerance of the configurationof the casing of the rear projector and the tolerance of the componentsinstalled in the casing so that the image displayed on the screen islocated beyond the screen frame, undisplayable area can be narrowed bythe planar position adjusting mechanism, thus displaying the image onthe entire screen.

[0023] In the rear projector according to an aspect of the presentinvention, the planar position adjusting mechanism may preferablycomprise a slide adjuster that adjusts the position of the imagegenerator in a direction along the screen and in normal line directionof the screen.

[0024] According to the above arrangement, since the planar positionadjusting mechanism has the slide adjuster, the planar position of theimage generator can be adjusted by moving the slide adjuster, thuseasily adjusting the planar position of the image generator.

[0025] In the rear projector according to an aspect of the presentinvention, a rotary position adjusting mechanism that adjusts rotaryposition of the image generator relative to the screen may preferably beprovided on the support base.

[0026] According to the above arrangement, since the support base isprovided with the rotary position adjusting mechanism, the rotation ofthe image generator that projects the optical image can be adjusted,thus optimizing the position shift caused by distortion or rotation ofthe image displayed on the screen.

[0027] In the above arrangement, the rotary position adjusting mechanismmay preferably adjust the rotation of the image generator around planarposition of the optical axis of the light beam irradiated by theprojection optical system.

[0028] When the image displayed on the screen is rotated relative to thescreen frame, the rotation of the displayed image has to be adjusted.During the rotation adjustment, if the rotation is adjusted when therotation center of the displayed image is remote from the displayedimage, the displayed image is rotated on the screen surface whilecausing planar movement.

[0029] Since the rotary position adjusting mechanism adjusts therotation of the image generator around the planar position of theoptical axis of the light beam irradiated by the projection opticalsystem, the image generator can be rotated around the main optical axisof the irradiated light beam when the rotation of the image generator isadjusted. In other words, the image displayed on the screen can berotated around the illumination optical axis of the displayed image,thus restraining planar movement of the image displayed on the screenand easily adjusting the rotation of the displayed image.

[0030] Accordingly, there is no need for adjusting the planar positionof the image generator after adjusting the rotation of the imagegenerator, thereby enhancing working efficiency.

[0031] In the rear projector according to an aspect of the presentinvention, both of the support plate and the support base may preferablybe provided with a screwing mechanism extending toward the opposingsupport plate or the support base, and the inclination positionadjusting mechanism may preferably be a screwing component having afirst end screwed to the screwing mechanism of the support plate and asecond end screwed to the screwing mechanism of the support base.

[0032] According to the above arrangement, since the support plate andthe support base have the screwing mechanism and the inclinationposition adjusting mechanism is a screwing component screwed to thescrewing mechanism, the inclination of the support base relative to thesupport plate can be changed with a simple structure. In other words,the inclination of the image generator can be easily adjusted.

[0033] In the rear projector according to the above aspect of thepresent invention, either one of the support plate and the support basemay preferably be provided with a screwing mechanism extending towardthe opposing support plate or the support base, and the inclinationposition adjusting mechanism may preferably be provided with a screwingcomponent having one end screwed to the screwing mechanism provided onone of the support plate and the support base and a convex componentprovided on the other end of the screwing component rotatably fitted toa concave portion formed on the other of the support plate and thesupport base.

[0034] According to the above arrangement, since one of the supportplate and the support base has the screwing mechanism and the concaveportion is formed on the other of the support plate and the supportbase, and since the inclination position adjusting mechanism is providedwith the screwing component and the convex portion, the plate base canbe moved in advancement and retraction position of the screwingdirection by advancing and retracting the screwing component relative tothe support plate, thus adjusting the inclination position of the imagegenerator.

[0035] Further, in an arrangement where the inclination positionadjusting mechanism is disposed at a plurality of locations, since theconvex portion rotatably fitted to the concave portion formed on theother of the support plate and the support base is provided on thesecond end of the screwing component, when the screwing component of oneof the plurality of inclination position adjusting mechanisms isadvanced and retracted, the engagement of the convex portion formed onthe second side of the screwing component and the concave portion formedon the bottom side of the casing can be changed, thus adjusting theinclination of the image generator in a torsional direction of the imagegenerator.

[0036] In the above, since the inclination position adjusting mechanism,the planar position adjusting mechanism and the rotary positionadjusting mechanism are provided on the support base, the inclinationposition, the planar position and the rotary position of the imagegenerator can be easily adjusted and the influence of the external forceapplied on the image generator in adjusting the position of the imagegenerator can be mitigated, thus preventing mutual position shiftbetween the respective optical systems in the image generator andobtaining stable projection image having constant aspect ratio.

[0037] A rear projector according to another aspect of the presentinvention comprises: an image generator having an electric opticaldevice that modulates a light beam irradiated by a light source andforms an optical image in accordance with image information and aprojection optical system that enlarges and projects the optical image;a box-shaped casing that houses the image generator; a screen exposed onone of the lateral sides of the box-shaped casing onto which the opticalimage generated by the image generator is projected; and a reflectionoptical system that is located on the optical path of the light beamirradiated by the projection optical system to reflect the light beamtoward the screen, the reflection optical system being attached to theinterior of the casing by a first holder holding the upper end and thelower end of the reflection optical system, in which an attitudeadjuster that adjusts the position of the optical axis of the reflectionoptical system in up-shift direction relative to the light beamirradiated by the projection optical system is provided on the firstholder on the upper end.

[0038] Normally, the casing that houses the image generator, thereflection optical system and the screen is formed by injection moldingetc., and slight dimension tolerance is inevitably caused in suchcasing.

[0039] When the reflection optical system such as mirror is fixed to thecasing, the mirror is bent on account of the slight dimension toleranceand there is projection dispersion in the images displayed on the screenon account of the change in the aspect ratio of the projected image.

[0040] According to the above aspect of the present invention, since thereflection optical system is attached to the interior of the casing bythe holder and the attitude adjuster is provided on the holder on theupper end, the up-shift direction of the optical axis of the reflectionoptical system can be adjusted by adjusting the attitude of thereflection optical system by the attitude adjuster.

[0041] Accordingly, even when the aspect ratio of the displayed image ischanged on account of the difference in tolerance of the configurationof the casing of the rear projector and the tolerance of the componentsinstalled in the casing causing projection dispersion on the imagedisplayed on the screen, optimization is possible by adjusting theattitude of the reflection optical system by the attitude adjuster,thereby displaying the image on the entire screen.

[0042] The reflection optical system may preferably be composed of anapproximately trapezoidal mirror, which can be arranged in a minimumshape required in accordance with the aspect ratio of the imageprojected by the image generator, so that the size and weight of therear projector can be reduced while sufficiently working as thereflection optical system.

[0043] In the rear projector according to an aspect of the presentinvention, the first holder on the upper end may preferably have agroove for an end of the reflection optical system to be inserted, and agap may preferably be formed between the end of the reflection opticalsystem and the bottom of the groove when the reflection optical systemis attached.

[0044] According to the above arrangement, since the holder on the upperend has the groove and a gap is formed between the end of the reflectionoptical system and the bottom of the groove when the reflection opticalsystem is attached, the end of the reflection optical system does notcollide with the bottom of the groove of the holder when the attitude ofthe reflection optical system is adjusted by the attitude adjuster,thereby preventing the external force being locally applied on the endof the reflection optical system.

[0045] Accordingly, the attitude of the reflection optical system can besmoothly adjusted by the attitude adjuster and distortion of thereflection optical system by the external force can be avoided bypreventing the external force being applied on the end of the reflectionoptical system, thus mitigating projection dispersion of the imagedisplayed on the screen.

[0046] In the rear projector according to an aspect of the presentinvention, an elastic member may preferably be interposed between asurface of the first holder and the surface of the reflection opticalsystem opposite to the reflection surface thereof.

[0047] According to the above arrangement, since the elastic member isinterposed between the surface of the first holder and the surface ofthe reflection optical system opposite to the reflection surfacethereof, damage on the end of the reflection optical system caused byfriction between the holder and the reflection optical system inaccordance with attitude adjustment of the reflection optical system bythe attitude adjuster can be mitigated.

[0048] Further, by the pressing force of the elastic member, thereflection surface of the reflection optical system is brought intocontact with the end of the holder and the attitude of the reflectionoptical system can be adjusted while keeping the contact there between.

[0049] Accordingly, there is no distortion on the reflection opticalsystem by adjusting the attitude of the reflection optical system by theattitude adjuster, thereby accurately maintaining the inclination of thereflection optical system.

[0050] In the rear projector according to an aspect of the presentinvention, the reflection optical system may preferably be attached tothe casing by a second holder holding the lateral side of the reflectionoptical system, and an elastic member may preferably be interposedbetween a surface of the second holder and the reflection surface of thereflection optical system.

[0051] According to the above arrangement, since the reflection opticalsystem is attached to the casing by the second holder holding thelateral side thereof and the elastic member is interposed between asurface of the second holder and the reflection surface of thereflection optical system, the self-weight of the reflection opticalsystem can be supported by the second holder, so that deformation of thereflection optical system caused by self-weight of the reflectionoptical system such as distortion can be prevented and change in aspectratio of the image displayed on the screen by the deformation can beavoided, thereby mitigating projection dispersion.

[0052] Further, since the elastic member is interposed on a surface ofthe second holder to be in contact with the reflection optical system,the end of the reflection optical system can be received by the elasticdeformation of the elastic member in adjusting the attitude of thereflection optical system by the attitude adjuster.

[0053] Accordingly, the end of the reflection optical system can bereceived by the elastic deformation of the elastic member in accordancewith inclination of the reflection optical system, thereby avoidingrestriction of the inclination of the reflection optical system by thefixed holder.

BRIEF DESCRIPTION OF THE DRAWINGS

[0054]FIG. 1 is a perspective view of a rear projector seen from frontside according to first embodiment of the present invention;

[0055]FIG. 2 is a perspective view of a rear projector seen from rearside according to the aforesaid embodiment of the present invention;

[0056]FIG. 3 is an exploded perspective view of a rear projector seenfrom rear side according to the aforesaid embodiment, which specificallyshows that a back cover is removed from FIG. 2;

[0057]FIG. 4 is an exploded perspective view of a rear projector seenfrom bottom side according to the aforesaid embodiment;

[0058]FIG. 5 is a vertical cross section showing a rear projectoraccording to the aforesaid embodiment;

[0059]FIG. 6 is a vertical cross section of a lower cabinet and a legseen from front side according to the aforesaid embodiment;

[0060]FIG. 7 is a perspective view of an interior unit seen from rearside according to the aforesaid embodiment;

[0061]FIG. 8 is a front elevational view of a rear projector accordingto the aforesaid embodiment where a screen is removed;

[0062]FIG. 9 is a perspective view showing an optical unit bodyaccording to the aforesaid embodiment;

[0063]FIG. 10 is a plan view schematically showing the optical unit bodyaccording to the aforesaid embodiment;

[0064]FIG. 11 is a plan view showing a rear projector according to theaforesaid embodiment;

[0065]FIG. 12 is a vertical cross section taken along XII-XII line inFIG. 11;

[0066]FIG. 13 is a perspective view showing a support member as anattitude adjuster seen from top side according to the aforesaidembodiment;

[0067]FIG. 14 is a cross section of an inclination adjuster according tothe aforesaid embodiment;

[0068]FIG. 15 is a cross section showing a rotation adjusting mechanismof an adjusting portion of the inclination adjuster according to theaforesaid embodiment;

[0069]FIG. 16 is an exploded perspective view of a mirror angle adjusteraccording to the aforesaid embodiment;

[0070]FIG. 17 is a cross section of a mirror angle adjuster according tothe aforesaid embodiment;

[0071]FIG. 18 is a cross section showing a holding mechanism of areflection mirror by a mirror receiver according to the aforesaidembodiment;

[0072]FIG. 19 is a cross section showing a holding mechanism of areflection mirror by a mirror support according to the aforesaidembodiment; and

[0073]FIG. 20 is an illustration schematically showing positionalrelationship of a base member, a support member and an optical unitaccording to second embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

[0074] [First Embodiment]

[0075] A first embodiment of the present invention will be describedbelow with reference to attached drawings.

[0076] [1-1. Primary Arrangement of Rear Projector]

[0077]FIG. 1 is a perspective view showing a rear projector seen fromfront side according to an aspect of the present invention. FIG. 2 is aperspective view of the rear projector 1 seen from rear side. FIG. 3 isan exploded perspective view of the rear projector 1 seen from rearside, which specifically shows that a back cover 14 is removed from FIG.2. FIG. 4 is an exploded perspective view of the rear projector 1 seenfrom bottom side. FIG. 5 is a vertical cross section showing the rearprojector 1.

[0078] Primary arrangement of the rear projector 1 will be describedbelow with reference to FIGS. 1 to 5.

[0079] As shown in FIGS. 1 to 5, the rear projector 1 modulates a lightbeam irradiated by a light source in accordance with image informationto form an optical image and enlarges and projects the optical image ona screen, which includes a cabinet 10 constituting a casing, a leg 20provided on the lower side of the cabinet 10, an interior unit 40located inside the cabinet 10, a reflection mirror 30 (FIG. 5) alsolocated inside the cabinet 10, and a screen 51 exposed on a side of thecabinet 10. The cabinet 10, the interior unit 40, the reflection mirror30 and the screen 51 construct a projector body.

[0080] Incidentally, for the convenience of explanation, left side seenfrom front side is referred to as left and right side seen from frontside is referred to as right in the present embodiment.

[0081] The cabinet 10 is a casing of synthetic resin for accommodatingthe interior unit 40 and the reflection mirror 30. As shown in FIGS. 2and 3, the cabinet 10 has a lower cabinet 13 of C-shaped vertical crosssection accommodating the interior unit 40 and covering approximatelyentire front, upper and lower sides and right and left sides, a backcover 14 covering the rear side and a part of the right and left sides,and an upper cabinet 12 of triangle vertical cross section disposedabove the lower cabinet 13.

[0082] The dimension of the lower cabinet 13 in right and left directionalong the surface of the screen 51 is smaller than the dimension of theupper cabinet 12 in right and left direction along the surface of thescreen 51.

[0083] The back cover 14 is detachably attached to the lower cabinet 13.

[0084] As shown in FIG. 4, the lower cabinet 13 includes a front side131, right and left lateral sides 132, an upper side 133 and a lowerside 134.

[0085] As shown in FIG. 4, a central portion 131A bulging toward frontside in accordance with projection of a projection lens constituting theinterior unit 40 is provided approximately at the center of the frontside 131. Rectangular openings 131R and 131L of approximately the samedimension are formed on both sides of the central portion 131A. Wooferboxes 60 (60R and 60L) as a speaker for reproducing low-pitched soundare respectively attached to the openings 131R and 131L. The wooferboxes 60R and 60L are attachable to and detachable from the openings131R and 131L from the front side.

[0086] Incidentally, though not clearly shown in the illustration,various device-connecting terminals such as connector for connecting acomputer, a video input terminal and audio-connection terminal areprovided on the lower side of the left opening 131L.

[0087] Further, as shown in FIG. 3, slit-shaped openings are formed onthe right and left lateral sides 132 of the lower cabinet 13. The leftopening is an intake opening 132L for introducing a cooling air into theinterior of the projector and the right opening is an exhaust opening132R for discharging the air having introduced and cooled the interior.

[0088] The upper side 133 opposes to a lower side of the upper cabinet12 (described below). The lower side 134 abuts to the receiver surfaceof the leg 20 (described below).

[0089] As shown in FIG. 3, the back cover 14 includes a rear side 141and right and left lateral sides 142.

[0090] A second intake opening 141A for introducing cooling air isformed on the right side (left side seen from rear side) of the rearside 141 of the back cover 14. An air filter 143 is attached to thesecond intake opening 141A. A cover 144 for shutting the second intakeopening 141A provided with the air filter 143 is detachably attached tothe opening 141A. An opening for inlet connector 145 is provided on theleft side (right side seen from rear side) of the second intake opening141A of the rear side 141.

[0091] Various device connection terminals such as connector forconnecting a computer, a video input terminal and audio-connectionterminal are provided on the left side (right side seen from rear side)of the rear side 141, and an interface board 80 is provided on the innersurface of the rear side 141.

[0092] As shown in FIGS. 2 and 5, the upper cabinet 12 is a casing oftriangle vertical cross section for accommodating the reflection mirror30, which includes a lower side 15 of approximately rectangle plate,right and left lateral sides 16 of triangle plate vertically extendingfrom both ends of the lower side 15, a rear side 17 spanning over theright and left sides and slanting toward the lower rear side, and afront side 18 of approximately rectangle plane. Rectangular opening 18Ais formed on the planar front side 18. A screen 51 covering the opening18A is attached to the front side 18.

[0093]FIG. 6 is a vertical cross section of the lower cabinet 13 and theleg 20 of the rear projector 1 seen from front side.

[0094] As shown in FIGS. 3, 4 and 6, the leg 20 is a synthetic resinmember supporting the projector body and covering a part of the frontside 131 of the lower cabinet 13, which includes a receiver surface 21to be abutted to the entire lower side 134 of the lower cabinet 13, anda rib-shaped support 22 surrounding the back side of the receiversurface 21 and having a predetermined height dimension.

[0095] A concave groove dented for a dimension corresponding to theheight of the support 22 is formed on the receiver surface 21, thegroove extending from the left side to the center of the central area infront and back direction.

[0096] As shown in FIG. 4, the backside of the support 22 abuts to asurface of floor etc. when the rear projector 1 is installed on a floorsurface or upper surface of desk. A reinforcing rib 22A of matrix-shapehaving a predetermined height is formed on the inner circumference ofthe support 22. The reinforcing rib 22A enhances the rigidity of the leg20 and prevents position shift from the floor surface etc.

[0097] A planar portion 22B having no reinforcing rib 22A is provided ona part of the inner area of the support 22, the planar portion 22Bextending from the left to the center of central area in front and backdirection on the backside of the support 22. The planar portion 22B isthe lower side of the concave groove formed on the receiver surface 21.

[0098] As shown in FIG. 6, when the projector body is mounted on thereceiver surface 21 having the concave groove, a third duct 93 extendingfrom the left lateral side 132 of the lower cabinet 13 to the centralportion in right and left direction is formed. However, the lower sideof the projector body does not abut to both peripheral ends of the thirdduct 93 so that the peripheral end around the left lateral side 132 andthe peripheral end at the approximate center are left open.

[0099] An end of a second duct 92 is connected to the opening adjacentto the left lateral side 132. The other end of the second duct 92 isconnected to the intake opening 132L formed on the left lateral side 132through an air filter 135.

[0100] An end of fourth duct 94 is connected to an opening on thecentral peripheral end at the central portion. The other end of thefourth duct 94 is disposed on the lower side of an optical deviceconstituting the projector body through an elastic member such as asponge.

[0101]FIG. 7 is a perspective view of the interior unit seen from rearside.

[0102] As described below in detail, the interior unit 40 is a devicelocated on the receiver surface 21 of the leg 20 for forming apredetermined optical image in accordance with inputted imageinformation and outputting sound and image by amplifying the soundsignal added to the image information.

[0103]FIG. 8 is a front elevational view with the screen 51 beingremoved from the rear projector 1.

[0104] The reflection mirror 30 is an ordinary reflection mirror ofapproximately trapezoidal shape, which is attached to the inside of therear side 17 of the upper cabinet 12 so that the long side of thetrapezoid comes to the upper side. A mirror holder 31 as a holder forholding the reflection mirror 30 at a predetermined position is formedon an inner side of the rear side 17 of the upper cabinet 12. The mirrorholder 31 holds the long side, short side and oblique sides of thereflection mirror 30 so that there is no distortion on the reflectionmirror 30.

[0105] As shown in FIG. 1, the screen 51 is a transmissive screen onwhich the optical image enlarged in the interior unit body 400 andreflected by the reflection mirror 30 is projected from the backside.The screen 51 has a screen 51 and a screen cover 52 for accommodatingthe screen 51 with the front side of the screen 51 being exposed.

[0106] As shown in FIG. 2, speaker boxes 70 are respectively attached tothe right and left lateral sides 16 of the upper cabinet 12 as a bodyindependent of the upper cabinet 12. The speaker box 70 is a box-shapedbody working as a speaker. The front side of the speaker box 70 issubstantially flush with the front side of the screen 51 so that theboth sides are approximately parallel in vertical direction.

[0107] As shown in FIG. 1, the screen cover 52 is fixed to the uppercabinet 12 with the screen 51 being accommodated and the front side 18of the upper cabinet 12 and the front side of the speaker box 70 beingcovered.

[0108] [1-2 Arrangement of Interior Unit]

[0109] As shown in FIG. 7, the interior unit 40 has a interior unit body400, a power source block 300 for supplying electric power to theinterior unit body 400 or a below-described sound signal amplifier 307(amplifier), and a base member 201 for supporting the interior unit body400 and the power source block 300.

[0110] As shown in FIG. 7, the interior unit body 400 has a light source411 located on the left side, which includes an optical unit 401 ofplanarly-viewed L-shape extending from the light source 411 to the rightand further front side, and a support member 200 as a support base thatsupports the optical unit 401 to adjust position thereof.

[0111] Though described below in detail, as shown in FIG. 7, the opticalunit 401 has an optical unit body 401A as an image generator foroptically processing the light beam emitted by the light source 411 toform an optical image in accordance with image information, and acontrol board 402 covering a part of the right side of the optical unitbody 401A to extend from the center to the left side (right side seenfrom rear side).

[0112] The control board 402 has a controller having CPU etc., whichcontrols the drive of the optical device as a component of the opticalunit body 401A in accordance with inputted image information and islocated to cover a part of the right side of the optical unit body 401Ato be extended to the right side.

[0113] The control board 402 is surrounded by a metal shield 403 and isattached to the support member 200 to span over the optical unit body401A through a column member.

[0114] As shown in FIG. 7, the power source block has a first powersource 301 provided on the front side of the light source 411, and asecond power source 302 provided on the left side of a partition 205seen from rear side.

[0115] The first power source 301 includes a first power source 303 anda lamp driving circuit (ballast) 304 adjacent to the first power source303.

[0116] The first power source 303 supplies electric power fed from theoutside to the lamp driving circuit 304, the control board 402 etc.through a not-illustrated power cable connected to the inlet connector145.

[0117] The lamp driving circuit 304 supplies electric power fed from thefirst power source 303 to the light source lamp constituting the opticalunit 401, which is electrically coupled with the light source lamp. Thelamp driving circuit 304 is, for instance, wired to a non-illustratedboard.

[0118] The first power source 301 is covered with a metal shield 305with right and left sides being opened, thereby preventing leakage ofelectromagnetic noise from the first power source 303 and the lampdriving circuit 304.

[0119] An axial-flow fan 521 is attached to a center opening of theshield 305 on the right side seen from rear side, which blows coolingair in a direction in which the first power source 301 extends, i.e.from the central portion to the right side. According to thearrangement, the shield 305 also works as a duct for guiding the coolingair.

[0120] The second power source 302 has a second power source 306 and asound signal amplifier 307 for amplifying the inputted sound signal.

[0121] The second power source 306 supplies electric power fed from theoutside to the sound signal amplifier 307 through a non-illustratedpower cable connected to the inlet connector 145.

[0122] The sound signal amplifier 307 is driven by the electric powersupplied by the second power source 306 to amplify the inputted soundsignal, which is electrically coupled with the speaker box and thewoofer box (not illustrated in FIG. 8). The sound signal amplifier 307is, for instance, wired to a non-illustrated board.

[0123] The base member 201 opposes to the receiver surface 21 of the leg20 to support the components of the interior unit 40, which isconstructed by metal plate member.

[0124] As shown in FIG. 7, the partition 205 for insulating heat betweenthe right and left spaces vertically extends from the upper side of thebase member 201 on the left side seen from the rear side. The partition205 spaces the first power source 301 and the light source 411 of theoptical unit 401, and the second power source 302 and insulates heatbetween the right and left spaces, thereby preventing heat migrationbetween the first power source 301 and the light source 411, and thesecond power source 302.

[0125] Further, an engaging groove engaging with a non-illustrated railmember provided on the receiver surface 21 of the leg 20 is provided onthe lower side of the base member 201, which is advanceable andretractable in front and back direction. In other words, the interiorunit 40 can be slidably taken out from the lower cabinet 13 to the rearside by the advancement and retraction of the base member 201.

[0126] [1-3. Detailed Construction of Optical System]

[0127]FIG. 9 is a perspective view showing an optical unit body 401A.FIG. 10 is a plan view schematically showing the optical unit body.

[0128] As shown in FIG. 10, the optical unit 401 is a unit for opticallyprocessing the light beam irradiated by a light source lamp as acomponent of the light source to form an optical image in accordancewith image information, which includes an integrator illuminatingoptical system 41, a color separating optical system 42, a relay opticalsystem 43, an optical device 44, a right-angle prism 48 and theprojection lens 46 as a projection optical system.

[0129] The integrator illuminating optical system 41 is a system forsubstantially uniformly illuminating the image formation area of thethree liquid crystal panels 441 constituting the optical device 44(respectively referred to as liquid crystal panel 441R, 441G and 441Bfor every color lights of red, green and blue), which includes a lightsource 411, a first lens array 412, a second lens array 413, apolarization converter 414 and a superposing lens 415.

[0130] The light source 411 has a light source lamp 416 as a radiationlight source and a reflector 417, which changes the radial light beamirradiated by the light source lamp 416 into a parallel light beam bythe reflector 417 to emit the parallel light beam toward the outside.

[0131] A halogen lamp is used as the light source lamp 416.Incidentally, metal halide lamp and a high-pressure mercury lamp etc.may be used instead of the halogen lamp.

[0132] A parabolic mirror is used as the reflector 417. Incidentally, acombination of a concave lens which parallelized nonparallel lightreflected by the reflector and an ellipsoidal mirror may be used insteadof the parabolic mirror.

[0133] The first lens array 412 is a plurality of small lenses arrangedin matrix, the lenses having substantially rectangular profile viewedfrom optical axis direction. The respective lenses split the beamemitted from the light source lamp 416 into a plurality of sub-beams.The profile of the respective lenses is approximately similar to theconfiguration of the image formation area of the liquid crystal panel441. For instance, when the aspect ratio (ratio of horizontal andvertical dimensions) of the liquid crystal panels 441 is 4:3, the aspectratio of the respective lenses is also set as 4:3.

[0134] The second lens array 413 has approximately the same arrangementas the first lens array 412, where the small lenses are disposed inmatrix. The second lens array 413 as well as the superposing lens 415focuses the image from the respective small lenses of the first lensarray 412 onto the liquid crystal panel 441.

[0135] The polarization converter 414 is disposed between the secondlens array 413 and the superposing lens 415 and is integrated with thesecond lens array 413 as a unit. The polarization converter 414 convertsthe light from the second lens array 413 to a single polarized light inorder to enhance light utilization efficiency in the optical device 44.

[0136] Specifically, the respective sub-beams converted into singlepolarized light by the polarization converter 414 are substantiallysuperposed on the liquid crystal panel 441 of the optical device 44 bysuperposing lens 415. Since the rear projector 1 using the liquidcrystal panel 441 for modulating polarized light can use only singlepolarized light, approximately half of the light from the light sourcelamp 416 emitting other random polarized light cannot be used.Accordingly, by using the polarization converter 414, all of the lightemitted from the light source lamp 416 is converted into singlepolarized light to enhance light utilization efficiency in the opticaldevice 44.

[0137] Incidentally, such polarization converter 414 is disclosed in,for instance, Japanese Patent Laid-Open publication No. Hei 8-304739.

[0138] The color separating optical system has two dichroic mirrors 421and 422 and a reflection mirror 423, the dichroic mirrors 421 and 422separating the plurality of sub-beams irradiated by the integratorilluminating optical system 41 into three color lights of red (R), green(G) and blue (B).

[0139] The relay optical system 43 has incident-side lens 431, a relaylens 433 and reflection mirrors 432 and 434, and introduces the redcolor light separated by the color separating optical system 42 onto theliquid crystal panel 441R.

[0140] At this time, the red light component and the green lightcomponent of the light beam irradiated from the illuminating opticalintegrator system 41 are transmitted through the dichroic mirror 421 ofthe color separating optical system 42 and the blue light component isreflected by the dichroic mirror 421. The blue light reflected by thedichroic mirror 421 is reflected by the reflection mirror 423, whichreaches to the liquid crystal panel 441B for blue-color through a fieldlens 418. The field lens 418 converts the respective sub-beams emittedfrom the second lens array 413 into a light beam parallel to centralaxis (main beam) thereof. The field lenses 418 provided in front of theother liquid crystal panels 441G and 441B function in the same manner.

[0141] In the red light and the green light transmitted through thedichroic mirror 421, the green light is reflected by the dichroic mirror422 to reach the liquid crystal panel 441G for green color through thefield lens 418. On the other hand, the red color transmits through thedichroic mirror 422 to pass the relay optical system 43 and reach theliquid crystal panel 441R for red color through the field lens 418.

[0142] Incidentally, the relay optical system 43 is used for the redcolor light in order to prevent decrease in utilization efficiency oflight on account of light diffusion caused by longer length of theoptical path of the red light than the length of the optical path of theother color lights. In other words, in order to directly transmit thesub-beam incident on the incident-side lens 431 to the field lens 418.

[0143] The optical device 44 is for modulating the incident light beamin accordance with image information to form a color image, which hasthree incident-side polarization plates 442, the liquid crystal panels441R, 441G and 441B disposed on the after-stage of the respectiveincident-side polarization plates 442 as optical modulators, anirradiation-side polarization plate 443 disposed on the after-stage ofthe respective incident-side polarization plates 442, and a crossdichroic prism 444 as a color combining optical system.

[0144] The liquid crystal panels 441R, 441G and 441B use, for instance,a polysilicon TFT as a switching element.

[0145] In the optical device 44, the color lights separated by thecolor-separating optical system 42 are modulated by the three crystalpanels 441R, 441G and 441B, the incident-side polarization plate 442 andthe irradiation-side polarization plate 443 in accordance with imageinformation to form an optical image.

[0146] The incident-side polarization plate 442 transmits only apolarized light of a predetermined direction among the respective colorlights separated by the color separating optical system 42 and absorbsthe other light beam, which is constructed by forming a polarizationfilm on a substrate of sapphire glass etc.

[0147] The irradiation-side polarization plate 443 is constructed in anapproximately the same manner as the incident-side polarization plate442, which transmits only a polarized light of a predetermined directionamong the light beam irradiated by the liquid crystal panels 441 (441R,441G and 441B) and absorbs the other light beam.

[0148] The polarization axes of the incident-side polarization plate 442and the irradiation-side polarization plate 443 are set orthogonal witheach other.

[0149] The cross-dichroic prism 444 combines the optical imageirradiated by the irradiation-side polarization plate 443 and modulatedfor respective color lights to form a color image.

[0150] A dielectric multi-layer film for reflecting red color light anda dielectric multi-layer film for reflecting blue color light are formedalong boundary of four right-angled prisms of the cross dichroic prism444, the dielectric multi-layer films combining three color lights.

[0151] The above-described liquid crystal panels 441, theirradiation-side polarization plate 443 and the cross dichroic prism 444are constructed as an integrated unit of optical device body 45.Incidentally, the incident-side polarization plate 442 is slidablyfitted and attached to a groove (not shown) formed on the light guide47.

[0152] Though not specifically shown, the optical device body 45 has thecross dichroic prism 444, a metal base for supporting the cross dichroicprism 444 from the lower side, a metal holding plate for holding theincident-side polarization plate 443 attached to the light-beam incidentend of the cross dichroic prism 444, and liquid crystal panels 441(441R, 441G and 441B) held by four pins 453 attached to thelight-beam-incident side of the holding plate. A predetermined gap issecured between the holding plate and the liquid crystal panel 441, sothat the cooling air flows through the gap.

[0153] The right-angle prism 48 is located on light-irradiation side ofthe cross dichroic prism 444 of the optical device 44, which bends andreflects the color image combined by the cross dichroic prism 444 in adirection of the projection lens 46, i.e. bends and reflects theforwardly-irradiated color image in upward direction.

[0154] The projection lens 46 enlarges to project the color imagereflected by the right-angle prism 48 on the reflection mirror 30. Theprojection lens 46 is supported by a non-illustrated head componentscrewed to the support member 200.

[0155] As shown in FIG. 7, a box-shaped cover 49A having open upper sideis provided around the projection side of the projection lens 46. Anopening for securing optical path of the projected optical image isformed around the lower side 15 of the upper cabinet 12. The cover 49Aabuts to the surrounding of the opening through an elastic member toenclose the opening.

[0156] The above-described optical systems 41 to 44 and 48 areaccommodated in a light guide 47 made of synthetic resin as an opticalcomponent casing shown in FIG. 9.

[0157] Though specific illustration of the inside of the light guide 47is omitted, as shown in FIG. 9, the light guide 47 has a lower lightguide 471 having the groove for the respective optical components 412 to415, 418, 421 to 423, 431 to 434 and 442 (FIG. 10) to be slidably fittedfrom the above, and a lid-shaped lower light guide 472 for closing theupper opening side of the lower light guide 471.

[0158] The above-described optical unit body 401A is supported by thesupport member 200 through a fixing hole 471A (FIG. 9) provided on theouter circumference of the lower light guide 471, where the attitude ofthe optical unit body 401A is adjusted to adjust the aspect ratio of thedisplayed image projected on the screen 51.

[0159] [1-4. Structure of Interior Cooling Mechanism]

[0160]FIG. 11 is a plan view showing the rear projector 1. FIG. 12 is avertical cross section taken along XII-XII line in FIG. 11.

[0161] As shown in FIGS. 7, 11 and 12, the rear projector 1 is providedwith an interior cooling area 500 for cooling the components 400, 200,301 and 302 constituting the interior unit 40 and the inside of thecabinet 10. The interior cooling area 500 cools the entirety of theinside of the lower cabinet 13 including the interior unit 40.

[0162] As shown in FIGS. 12 and 13, the interior cooling area 500introduces external cooling air from the intake opening 132L to theinside of the lower cabinet 13 to cool the respective components 400,200, 301 and 302 inside the lower cabinet 13 and discharges the airhaving cooled the components from the exhaust opening 132R on the rightside to the outside. In other words, a cooling channel for flowing thecooling air from the left side to the right side along the front side ofthe screen 51 is formed in the lower cabinet 13.

[0163] The interior cooling area 500 has a control board cooling channel511, an optical device cooling channel 512, a light source coolingchannel 513 and a power source cooling channel 514.

[0164] In the interior cooling area 500, as shown in FIGS. 12 and 13, apart of the external cooling air introduced from the intake opening 132Lby axial-flow fans 522 and 523 is drawn in by the axial-flow fan 522 tocool the control board 402 while flowing along the control board coolingchannel 511. A part of the rest of the cooling air is drawn by theaxial-flow fan 523 and a sirocco fan 524 to flow in the optical devicecooling channel 512 including the second to fourth ducts 92 to 94 tocool the optical device 44. The cooling air joins around the upper sideof the optical device 44.

[0165] A first duct 91 disposed on the right side of the partition 205extending in front and back direction is used in the light sourcecooling channel 513.

[0166] A part of the joined air is drawn by two sirocco fans 525 and 526for cooling optical components as shown in FIG. 11, which flows in thelight source cooling channel 513 in the light guide 47 to cool thepolarization converter and the light source and subsequently flows inthe first duct 91 to be discharged from the exhaust opening 132R to theoutside.

[0167] On the other hand, the rest of the joined air is drawn by theaxial-flow fan 521 to flow through the power source cooling channel 514to cool the first power source 301 and the second power source 302,which is discharged from the exhaust opening 132R to the outside.

[0168] Two channels are provided as the exhaust channel for the airhaving cooled the components. The air having cooled the light source 411is directly discharged to the outside through the dedicated first duct91 without being in contact with the other components so as to avoidinterference with the second power source 302.

[0169] [1-5. Attitude Adjusting Mechanism of Optical Unit Body]

[0170] Attitude adjusting mechanism of optical unit body 401A will bedescribed below.

[0171]FIG. 13 is a perspective view showing the support member 200 as asupport base seen from above.

[0172] The support member 200 adjusts the projection direction of theoptical unit body 401A in order to project the optical image projectedby the optical unit body 401A onto the backside of the screen 51 via thereflection mirror 30. The support member 200 has lateral positionadjusters 202 as planar position adjusting mechanism provided on thebase member 201 of the interior unit 40 in an opposing manner, aninclination adjuster 203 as an inclination adjusting mechanismvertically mounted on the lateral position adjusters 202, and a rotaryposition adjuster 204 as a rotation adjusting mechanism attached to theinclination adjuster 203 in a manner slanted to the rear side.

[0173] Though specific illustration is omitted, the lateral positionadjuster 202 is a base of the inclination adjuster 203 and the rotationadjuster 204 for adjusting planar position of the entire support member200. The lateral position adjuster 202 is constructed by anapproximately planarly-viewed F-shaped plate body configured inaccordance with the shape of the optical unit body 401A.

[0174] Track 202A of laterally elongated configuration disposed on aplurality of locations and a rising piece 202B formed by bending theouter circumference of the plate body are provided on the plate body.

[0175] The planar position of the optical unit body 401A is fixed byinserting a screw to the loose hole 202A to be screwed to anon-illustrated hole formed on the bottom surface of the lower cabinet.

[0176] In order to adjust the planar position of the optical unit body401A, the screw inserted to the loose hole 202A is loosened and therising piece 202B is held to move the lateral position adjuster 202along the profile of the loose hole 202A, so that the optical unit body401A is laterally moved, thereby adjusting planar position thereof.

[0177] Incidentally, though the loose hole 202A is laterally elongatedin the present embodiment, the loose hole 202A may be elongated in frontand back direction in order to move the optical unit body 401A in frontand back direction or, alternatively, the loose hole 202A may be shapedin a cross extending both in lateral direction and front and backdirection.

[0178] The inclination adjuster 203 adjusts inclination position of theoptical unit body 401A in up-shift direction relative to the screen. Theinclination adjuster 203 is fixed on the upper side of the lateralposition adjuster, which includes a leg 203A for supporting theinclination adjuster 203, a column 203B supported by the leg 203A andvertically mounted on the upper side of the lateral position adjuster202, and a movable metal fitting 203C connected to the distal end of thecolumn 203B to be fixed to the rotary position adjuster 204.

[0179]FIG. 14 is a cross section of the inclination adjuster 203.

[0180] The column 203B is provided with a spherical body 203B formedapproximately in a sphere at a base end thereof, the spherical body 203Bbeing engaged with the leg 203A. External thread is formed at the distalend thereof to be screwed to the movable metal fitting 203C. A rotaryknob 203B1 for allowing rotation of the column 203B is formed at thecenter thereof.

[0181] The leg 203A is provided with a concave portion 203A1 configuredaccording to the shape of the spherical body 203B2. The leg 203A isscrewed and fixed to the lateral position adjuster 202.

[0182] The movable metal fitting 203C is an approximately square pillar,in which a vertically penetrating hole 203C1 and a fixing hole 203C2piercing the side of the movable metal fitting 203C to the hole 203C1are formed.

[0183] A threaded hole for the distal end of the column 203B to bescrewed is formed on the inner circumference of the hole 203C1, so thatthe movable metal fitting 203C is advanced and retracted in longitudinaldirection of the column 203B according to screwing amount relative tothe column 203B.

[0184] A screw is inserted to the fixing hole 203C2 to fix screwing ofthe movable metal fitting 203C and the column 203B, thereby fixing theinclination position of the optical unit body 401A relative to thescreen 51 in up-shift direction.

[0185] Though specific illustration is omitted, the above-describedinclination adjuster 203 is provided on four locations of respectiveends and bent corner of the lateral position adjuster of approximatelyplanarly-viewed F-shape.

[0186] In order to adjust the inclination position of the optical unitbody 401A, the rotary knob 203B1 of the inclination adjuster 203 isrotated to change screwing amount of the distal end of the column 203and the movable metal fitting 203C to advance and retract the movablemetal fitting 203C in the longitudinal direction of the column 203B. Theoperation is conducted on the four inclination adjusters 203 disposed onthe lateral position adjuster 202, so that the inclination position ofthe rotary position adjuster 204 on which the optical unit body 401A isfixed can be adjusted, thereby adjusting the inclination position of theoptical unit body 401A in up-shift direction relative to the screen 51.

[0187] When the four inclination adjusters 203 are adjusted one by onein adjusting the inclination position, since only one of the movablemetal fittings 203C is advanced and retracted relative to the unadjustedthree inclination adjusters 203, the angle of the respective inclinationadjuster 203 relative to the lateral position adjuster 202 has to be setvariable. As described above, since the base end of the column 203B isprovided with the spherical body 203B2 of approximate sphere, which isengaged with the concave portion 203A1 of the leg 203A formed inaccordance with the shape of the spherical body 203B.

[0188] In other words, the inclination position of the optical unit body401A can be adjusted not only in up-shift direction relative to thescreen 51 but also in torsional (twist) direction.

[0189] As shown in FIG. 13, the rotary position adjuster 204 adjusts theposition of the optical unit body 401A in rotary direction on a plane.The rotary position adjuster 204 has a rotary member 204A for theoptical unit body 401A to be fixed, a rotary base member 204B engagedwith the rotary member 204A and connected with the inclination adjuster203, and an adjusting portion 204C connected with the rotary member 204Aand the rotary base member 204B.

[0190] The rotary member 204A is a plate configured substantiallyidentical with the optical unit body 401A having approximatelyplanarly-viewed L-shaped configuration, on which the optical unit body401A is mounted. The rotary member 204A has a rotation center 204A1engaging with the rotary base member 204B to be the rotation center ofthe rotary member 204A, and a rotation guide 204A2 remote from therotation center 204A1 to be engaged with the rotary base member 204B. Anopening 204A3 of approximate rectangle is formed on the rotary member204A for circulating cooling air to the optical unit body 401A.

[0191] A fourth duct 94 is provided in the opening 204A3 as a coolingchannel for circulating cooling air to the optical device.

[0192] The optical unit body 401A and the rotary member 204A are fixedby inserting a screw in fixing hole 471A (FIG. 9) formed on the outercircumference of the lower light guide 471 to be screwed to anon-illustrated hole formed on the rotary member 204A.

[0193] As described above, the boss is screwed on the upper side of therotary member 204A by which the projection lens 46 of the optical unitbody 401A is supported.

[0194] The rotation center 204A1 is a hole penetrating both sides of therotary member 204A, where the rotary member 204A and the rotary basemember 204B are engaged by inserting a screw to the hole and anon-illustrated hole formed on the rotary base member 204B, so that therotary member 204A can be rotated on the rotary base member 204B aroundthe rotation center 204A1.

[0195] The rotation center 204A1 is formed on the main optical axis ofthe light beam irradiated by the projection lens 46 of the optical unitbody 401A mounted on the rotary member 204A.

[0196] The rotary guide 204A2 is a track hole penetrating both sides ofthe rotary member 204A formed in rotary direction around the rotationcenter 204A1, which is engaged with a screw screwed and fixed on therotary base member 204B to guide the rotary member 204A.

[0197] Since the rotary member 204A and the rotary base member 204B arenot only connected by the rotation center 204A1 but also by the rotationguide 204A2, the rotary member 204A can be supported more securely bythe rotary base member 204B and the rotary member 204A can be rotatedmore smoothly relative to the rotary base member 204B.

[0198] The rotary base member 204B engages with the rotary member 204Ato support the rotation of the rotary member 204A, which is slightlylarger than the rotary member 204A.

[0199] A non-illustrated hole is formed on the rotary base member 204Bcorresponding to the rotation center 204A1 and the rotation guide 204A2of the rotary member 204A, and a non-illustrated opening to be a coolingchannel of cooling air is formed on the rotary base member 204Bcorresponding to the opening 204A3 of the rotary member 204A.

[0200] A non-illustrated hole is formed corresponding to the position ofthe below-described adjusting portion 204C.

[0201] A movable metal fitting 203C of the above-described inclinationadjuster 203 is fixed to the lower side of the rotary base member 204B,so that the inclination position of the rotary base member 204B changesin accordance with advancement and retraction of the movable metalfitting 203C.

[0202] The adjusting portion 204C rotates the rotary member 204Arelative to the rotary base member 204B. The adjusting portion 204C isdisposed on the lower side of the rotary base member 204B and the rotarymember 204A and on a surface remote from the position of the projectionlens 46 and extending toward the light source 411.

[0203]FIG. 15 is a cross section showing rotation adjusting mechanism ofthe adjusting portion 204C.

[0204] The adjusting portion 204C has a fixed portion 204C1 fixed on thelower side of the rotary base member 204B, a movable portion 204C2 fixedto the lower side of the rotary member 204A and a rotation adjustingscrew 204C3 connecting the fixed portion 204C1 and the movable portion204C2.

[0205] The fixed portion 204C1 and the movable portion 204C2 aredisposed in parallel in the front and back direction of the optical unitbody 401A. When the rotary member 204A is disposed on the rotary basemember 204B, the movable portion 204C2 is inserted to the hole 204B1formed on the rotary base member 204B.

[0206] The fixed portion 204C1 is an approximately square pillar, onwhich a stepped hole 204C4 penetrating both sides of the fixed portion204C1 in front and back direction of the optical unit body 401A isformed.

[0207] The rotation adjusting screw 204C3 is inserted to the hole 204C4,so that a screw-receiving surface 204C5 of the hole and rotary end ofthe rotation adjusting screw 204C3 are abutted.

[0208] The movable portion 204C2 is of approximately square pillarsimilar to the fixed portion 204C1, on which a hole 204C6 penetratingthe sides of the movable portion 204C2 of the optical unit body 401A infront and back direction is formed.

[0209] The hole 204C6 is provided with a threaded hole corresponding tothe external thread of the rotation adjusting screw 204C3 for therotation adjusting screw 204C3 to be screwed.

[0210] The rotation adjusting screw 204C3 is provided with an externalthread at a portion projecting from the fixed portion 204C1 when therotation adjusting screw 204C3 is inserted to the hole 204C4 of thefixed portion 204C1.

[0211] A nut 204C7 is fixed to an end of the external thread formed fromthe distal end of the rotation adjusting screw 204C3, thereby forcingthe rotation adjusting screw 204C3 to the fixed portion 204C1.

[0212] Since the rotation adjusting screw 204C3 is thus forced, therotation adjusting screw 204C3 does not move in front and back directionrelative to the fixed portion 204C1.

[0213] When the rotation of the optical unit body 401A is adjusted, therotation adjusting screw 204C3 inserted to the fixed portion 204C1 ofthe rotary position adjuster 204 is rotated by a screwdriver etc. Then,the movable portion 204C2 advances and retracts in the longitudinaldirection of the rotation adjusting screw 204C3 in accordance withchange in the screwing amount of the rotation adjusting screw 204C3 andthe movable portion 204C2. In other words, the rotary member 204A turnson the rotary base member 204B around the rotation center 204A1.Accordingly, the optical unit body 401A turns on the rotary base member204B together with the rotary member 204A, thus adjusting the rotationof the optical unit body 401A.

[0214] According to thus-constructed support member 200, the attitude ofthe optical unit body 401A can be adjusted in lateral direction,inclination direction and rotary direction relative to the upper side ofthe base member 201 of the interior unit 40.

[0215] [1-6. Holding Structure of Reflection Mirror]

[0216] Next, holding structure of the reflection mirror 30 according tothe present invention will be described below.

[0217] The reflection mirror 30 reflects the optical image projectedfrom the optical unit body 401A toward the screen 51. The reflectionmirror 30 is held by a mirror holder 31 formed on the rear side 17 ofthe upper cabinet 12. The reflection surface of the reflection mirror 30is slanted downward while being held.

[0218] As shown in FIG. 8, the mirror holder 31 holds the reflectionmirror 30 with a predetermined gap retained from the projection lens 46(FIG. 7) of the optical unit body 401A and adjusts the aspect ratio ofthe displayed image projected on the screen 51. The mirror holder 31 hasa mirror attitude adjuster 32 for supporting a long side ofapproximately trapezoidal reflection mirror 30, a mirror receiver 33supporting oblique side of the reflection mirror and a mirror support 34supporting the short side of the reflection mirror 30.

[0219]FIG. 16 shows an exploded perspective view of the mirror attitudeadjuster 32.

[0220]FIG. 17 shows a cross section of the mirror attitude adjuster 32.

[0221] As shown in FIG. 16, the mirror attitude adjuster 32 supports thelong side of the reflection mirror 30 so that the mirror attitudeadjuster 32 is vertically movable relative to the reflection surface.The mirror attitude adjuster 32 has a fixed portion 32A connected to therear side 17 of the upper cabinet 12, a holding portion 32B freelyfitted to the fixed portion 32A and holding the long side of thereflection mirror 30.

[0222] The fixed portion 32A is formed in approximately L-shaped crosssection and is provided with holes 32A1 to be connected with holesformed on the rear side 17 of the upper cabinet 12 on one of thesurfaces thereof and holes 32A2 to be connected with the holding portion32B on the other surface.

[0223] The hole 32A2 to be connected with the holding portion 32B is aloose hole elongated in a direction away from the upper cabinet, where ascrew is inserted to the hole 32A2 and a hole formed on thebelow-described holding portion 32B to fix the fixed portion 32A and theholding portion 32B.

[0224] The holding portion 32B is constructed by a plate body 32B1 andtwo support pieces 32B2 vertically mounted on the plate body 32B1, theholding portion 322B having a cross section of approximate F-shape.

[0225] A hole 32B3 to be connected with the hole 32A2 formed on thefixed portion 32A is formed on the plate body 32B1.

[0226] As shown in FIG. 17, an end of the reflection mirror 30 is heldbetween the two support pieces 32B2 as a support groove and a gap 32B4is formed between the edge of the reflection mirror 30 and the platebody 32B1.

[0227] An elastic member 32C is attached to one of the support piece32B2 located on the side of the upper cabinet. When the edge of thereflection mirror 30 is held by the support piece 32B2, the elasticmember 32C is in contact with the side opposite to the reflectionsurface of the reflection mirror 30.

[0228] The attitude of the reflection mirror 30 is adjusted using theabove-described mirror attitude adjuster 32 by loosening the screwscrewed to the hole 32A2 of the fixed portion 32A and the hole 32B3 ofthe holding portion 32B and moving the holding portion 32B relative tothe fixed portion 32A in a elongated direction of the hole 32A2 of thefixed portion 32A, i.e. in a vertical direction relative to thereflection surface of the reflection mirror 30.

[0229] When the holding portion 32B is moved relative to the fixedportion 32A in adjusting the attitude of the reflection mirror 30, theedge of the reflection mirror 30 abuts to the edge of the support piece32B2, so that torsion of the reflection mirror 30 can be restrained andthe reflection mirror is adjusted only in up-shift direction.

[0230] Further, since the side opposite to the reflection surface of thereflection mirror 30 abuts to the elastic member 32C, the differencebetween the inclination angle of the reflection mirror 30 and the angleof support piece 32B2 from the plate body 32B1 can be absorbed byphysical deformation of the elastic member 32C, so that the edge of thereflection mirror 30 can be constantly abutted to the support piece 32B2by virtue of the pressing force of the elastic member 32C.

[0231] As shown in FIG. 8, the mirror angle adjuster 32 is formed onthree locations on the long side of the reflection mirror 30 to adjustthe attitude of the reflection mirror 30.

[0232] Incidentally, though the mirror attitude adjuster 32 is formed onthree positions of the long side of the reflection mirror 30, the mirrorattitude adjuster 32 may be located on one or two positions foradjusting the attitude of the mirror.

[0233]FIG. 18 is a cross section showing holding mechanism of thereflection mirror 30 by the mirror receiver 33.

[0234] The mirror receiver 33 holds the self-weight of the reflectionmirror 30, which is located on the oblique side of the reflection mirror30 and is disposed at a boss 17A protruding from the rear side 17 of theupper cabinet 12.

[0235] In FIG. 18, vertical direction shows the inclination direction ofthe reflection mirror, and the lower side of the reflection mirrorcorresponds to the reflection surface.

[0236] The mirror receiver 33 has approximate Z-shaped cross section, ofwhich one end is fixed to the boss 17A and the other end abuts to thereflection mirror 30.

[0237] An elastic member 33A is attached to the side of the mirrorreceiver 33 abutting to the reflection mirror 30, so that the elasticmember 33A is interposed between the mirror receiver 33 and thereflection mirror.

[0238] Since the elastic member 33A is interposed, the elastic member33A is elastically deformed in accordance with adjustment of theattitude of the reflection mirror 30 by the mirror attitude adjuster 32,thereby responding to the inclination of the reflection mirror 30.

[0239] As shown in FIG. 8, two mirror receivers 33 are respectivelyformed on the oblique sides of the reflection mirror to avoid distortiondue to self-weight of the reflection mirror 30.

[0240] Incidentally, though two mirror receivers 33 are providedrespectively on the oblique side of the reflection mirror, only onemirror receiver 33 may be provided thereto.

[0241]FIG. 19 is a cross section showing holding mechanism of thereflection mirror 30 by the mirror support 34.

[0242] The mirror support 34 responds to the attitude adjustment of thereflection mirror 30 by the mirror attitude adjuster 32 and holds theself-weight of the reflection mirror 30. The mirror support 34 projectsfrom the rear side 17 of the upper cabinet 12, and includes a first boss17B supporting an edge of the reflection mirror 30, a mirror stopper 34Afor holding the reflection surface of the reflection mirror 30, and asecond boss 17C protruding from the rear side 17 of the upper cabinet 12to be abutted to the side opposite to the reflection surface of thereflection mirror 30.

[0243] The first boss 17B is of approximate trapezoidal configuration,where an edge of the reflection mirror 30 is abutted to the oblique sideof the trapezoid.

[0244] The mirror stopper 34A prevents shift in the abutting position ofthe end of the reflection mirror and the oblique side of the first boss17B due to the self-weight of the reflection mirror or the attitudeadjustment of the reflection mirror. The mirror stopper 34A hasapproximate Z-shaped cross section, of which one of the bent portioncorresponds to the bent portion of the first boss 17B and the other bentportion corresponds to the corner formed by the oblique side of thefirst boss 17B and the reflection mirror.

[0245] The second boss 17C has an approximately triangle cross section,which prevents shift in the abutting position between the edge of thereflection mirror 30 and the oblique side of the first boss 17B. Anelastic member 34B is attached to the abutting surface against thereflection mirror 30.

[0246] The elastic member 34B elastically deforms in accordance withadjusting the attitude of the reflection mirror 30 and prevents abuttingposition shift of the edge of the reflection mirror 30 and the obliqueside of the first boss 17B by the pressing force against the reflectionmirror 30.

[0247] [1-7. Effect of First Embodiment]

[0248] According to the above-described embodiment, following advantagescan be obtained.

[0249] (1) Since the optical unit is provided with the support member200 having a lateral position adjuster 202, an inclination adjuster 203and the rotary position adjuster 204, the attitude of the optical unitfor projecting the image can be adjusted by three axes. Accordingly,undisplayable area of the projected image to the screen can be narrowedin adjusting the display position of the image projected by the opticalunit on the screen.

[0250] Therefore, even when aspect ratio of the displayed image ischanged due to difference in the tolerance of the cabinet 10 of the rearprojector 1 and the tolerance of the components installed in the cabinet10 to cause projection dispersion on the image displayed on the screen,optimization is possible by adjusting the attitude of the optical unitbody 401A by the support member 200, thereby displaying the image on theentire screen.

[0251] (2) Since the optical unit body 401A is inclined in up-shiftdirection relative to the screen, the dimension of the rear projector 1in a direction away from the screen, i.e. the thickness, can be reduced,thereby reducing the volume of the projector.

[0252] (3) Since the lateral position adjuster 202 is disposed on thesupport plate of the interior unit and has the loose hole 202A and therising piece 202B, the optical unit body 401A can be moved in right andleft direction of the support plate by loosening the screw inserted tothe loose hole 202A, holding the rising piece 202B and moving thelateral position adjuster 202 relative to the support plate.

[0253] Accordingly, the planar position adjustment of the optical unitbody 401A can be easily conducted and the influence of external forceapplied to the optical unit body 401A in adjusting the planar positionof the optical unit body 401A can be mitigated, thereby preventingmutual position shift of the respective optical systems in the opticalunit body 401A and projecting stable image having no change in aspectratio of the image.

[0254] (4) Since the rotary position adjuster 204 has the rotary member204A, the rotary base member 204B and the adjusting portion 204C, andthe rotary member 204A rotates on the rotary base member 204B around therotation center 204A1 while the rotation center 204A1 of the rotarymember 204A and the rotation guide 204A2 engage with the rotary basemember 204B, the rotation of the optical unit body 401A can be easilyadjusted, thereby adjusting the position of the image displayed on thescreen.

[0255] (5) Since the rotary position adjuster 204 is constructed by therotary member 204A and the rotary base member 204B, the rotation of theoptical unit body 401A is adjusted by rotating the rotary member 204Arelative to the rotary base member 204B as in the lateral positionadjuster 202, so that the influence of external force applied to theoptical unit body 401A in adjusting the rotary position of the opticalunit body 401A can be mitigated, thereby preventing mutual positionshift of the respective optical system in the optical unit body 401A andprojecting stable image having no change in aspect ratio thereof.

[0256] (6) Since the rotation center 204A1 of the rotary member 204A isformed on the main optical axis of the light beam irradiated by theoptical unit body 401A, when the rotary member 204A is rotated relativeto the rotary base member 204B, the optical unit body 401A can berotated around a rotation center of the irradiated main optical axis,i.e. the displayed image projected on the screen can be rotated aroundthe illumination optical axis of the displayed image, so that the planarmovement of the image displayed on the screen can be restrained, therebyeasily adjusting the rotation of the displayed image.

[0257] Accordingly, the planar position adjustment of the optical unitbody 401A is not necessary after adjusting the rotation of the opticalunit body 401A, thus improving operation efficiency.

[0258] (7) Since the rotary member 204A and the rotary base member 204Bare connected by the adjusting portion 204C, the rotary member 204A canbe moved relative to the rotary base member 204B by rotating therotation adjusting screw 204C3 of the adjusting portion 204C by ascrewdriver etc.

[0259] (8) Since the rotation of the optical unit body 401A can beconducted by the adjusting portion 204C, the rotation of the opticalunit body 401A can be accurately adjusted within minute range.

[0260] (9) The inclination adjuster 203 has the leg 203A, the column203B and the movable metal fitting 203C and advances and retracts themovable metal fitting 203C along the longitudinal direction of thecolumn 203B by changing screwing amount of the distal end of the column203B and the movable metal fitting 203C with the lateral positionadjuster 202 and the rotary base member 204B of the rotary positionadjuster 204 being connected, i.e. moves the rotary base member 204Brelative to the lateral position adjuster 202. Accordingly, theinclination attitude of the optical unit body 401A can be adjusted inaccordance with the change in the screwing amount of the distal end ofthe column 203B and the movable metal fitting 203C.

[0261] (10) Since the base end of the column 203B of the inclinationadjuster 203 has the spherical body 203B2 which is engaged with the leg203A having the concave portion 203A1 shaped corresponding to thespherical body 203B2, when only one of the four inclination adjusters203 is adjusted, so that the inclination of the optical unit body 401Acan be adjusted by changing the engagement of the spherical body 203B2of the column 203B and the leg 203A even when the optical unit body 401Ais located in distorted manner relative to mere inclination thereof.

[0262] (11) Since the support member 200 is disposed on the base member201 in an inclined manner and the optical unit body 401A is supported onthe support member 200, the optical unit body 401A can be securelysupported in accordance with attitude adjustment of the optical unitbody 401A.

[0263] (12) Since the mirror holder 31 has the mirror attitude adjuster32, the long side of the reflection mirror 30 can be inclined in adirection orthogonal with the reflection surface thereof, i.e. up-shiftdirection of the reflection mirror 30, by moving the holding portion 32Bof the mirror attitude adjuster 32 relative to the fixed portion 32A.

[0264] Accordingly, even when the aspect ratio of the displayed image ischanged by the difference in the tolerance of the cabinet 10 of the rearprojector and the tolerance of components installed inside the cabinet10 to cause projection dispersion on the image displayed on the screen,optimization is possible by adjusting the attitude of the reflectionmirror 30 by the mirror attitude adjuster 32, thereby displaying theimage on the entire screen.

[0265] (13) Since the reflection mirror is formed in approximatetrapezoid which works minimum in accordance with the aspect ratio of theimage projected by the optical unit body 401A, the size and weight ofthe reflection mirror 30 can be reduced while sufficiently working asthe reflection mirror, thereby achieving size and weight reduction ofthe rear projector 1.

[0266] (14) Since the holding portion 32B of the mirror attitudeadjuster 32 is constructed by the plate body 32B1 and two support pieces32B2 vertically mounted on the plate body 32B1 and the gap 32B4 isformed between the reflection mirror 30 and the plate body 32B1 when thereflection mirror 30 is held between the two support pieces 32B2, theedge of the reflection mirror 30 does not collide with the plate body32B1 of the holding portion 32B, thereby avoiding locally applyingexternal force on the edge of the reflection mirror 30.

[0267] Accordingly, the attitude of the reflection mirror 30 can besmoothly adjusted by the mirror attitude adjuster 32, and since theexternal force is not applied to the edge of the reflection mirror 30,distortion of the reflection mirror 30 caused by external force can beavoided and projection dispersion of the image displayed on the screencan be mitigated.

[0268] (15) In the holding portion 32B of the mirror attitude adjuster32, since the elastic member 32C is attached to the support piece 32B2located on the side of the upper cabinet and the elastic member 32Cabuts to the side of the reflection mirror 30 opposite to the reflectionsurface thereof, the damage on the edge of the reflection mirror causedby the friction between the support piece 32B2 and the reflection mirror30 in accordance with adjustment of the attitude of the reflectionmirror 30 can be mitigated.

[0269] (16) Since the elastic member 32C is attached to the supportpiece 32B2 located on the side of the upper cabinet, the elastic member32C presses the side of the reflection mirror 30 opposite to thereflection surface thereof and the reflection surface of the reflectionmirror 30 abuts to the other support piece 32B2. The attitude of thereflection mirror 30 can be adjusted interlocking with the movement ofthe holding portion 32B keeping abutment of the reflection surface withthe support piece.

[0270] Accordingly, there is no distortion on the reflection mirror30—in accordance with adjustment of the attitude of the reflectionmirror 30, thereby accurately maintaining the inclination of thereflection mirror 30.

[0271] (17) Since the mirror holder 31 has the mirror receiver 33supporting the oblique side of the reflection mirror 30 and the mirrorreceiver 33 supports the reflection surface of the reflection mirror 30,the self-weight of the reflection mirror 30 can be supported by themirror receiver 33, so that the deformation of the reflection mirror 30such as distortion caused by the self-weight of the reflection mirror 30can be prevented, thus avoiding change in the aspect ratio of the imagedisplayed on the screen caused by the deformation and mitigating theprojection dispersion.

[0272] (18) Since the elastic member 33A is attached to the surface ofthe mirror receiver 33 abutting to the reflection surface of thereflection mirror 30, the edge of the reflection mirror 30 can besupported by the elastic deformation of the elastic member 33A inadjusting the attitude of the reflection mirror 30 by the mirrorattitude adjuster 32.

[0273] Accordingly, the edge of the reflection mirror 30 can besupported by the elastic deformation of the elastic member 33A inaccordance with the inclination of the reflection mirror 30 and therestriction of the inclination of the reflection mirror 30 by the fixedmirror receiver 33 can be avoided.

[0274] (19) Since the mirror support 34 has the first boss 17B, thesecond boss 17C and the mirror stopper 34A, abutment position shift ofthe edge of the reflection mirror 30 from the first boss 17B caused byattitude adjustment of the reflection mirror 30 by the mirror attitudeadjuster 32 and the self-weight of the reflection mirror 30, so that thereflection mirror 30 can be securely supported.

[0275] (20) Since the elastic member 34B is attached to the abutmentsurface of the second boss 17C against the reflection mirror 30, theelastic member 34B causes elastic deformation in accordance withattitude adjustment of the reflection mirror 30 and abutment positionshift of the edge of the reflection mirror 30 against the oblique sideof the first boss 17B can be prevented by the pressing force of theelastic member 34B against the reflection mirror 30.

[0276] [Second Embodiment]

[0277] Next, second embodiment of the present invention will bedescribed below.

[0278] In the following description, the same reference numeral will beattached to the same structure or the same component as in the firstembodiment to omit or simplify detailed explanation thereof.

[0279] In the first embodiment, the base member 201 is provided in thecabinet 10 and is in contact with the receiver surface 21 of the leg 20.The support member 200 is disposed on the base member 201 and theoptical unit body 401A is supported by the support member 200.

[0280] On the other hand, the base member 201 is spaced apart from thereceiver surface 21 of the leg 20 in the cabinet 10 in the secondembodiment. The support member 200 is disposed on the lower side of thebase member 201 and the optical unit body 401A is supported by thesupport member 200.

[0281] [2-1. Attitude Adjusting Mechanism of Optical Unit Body]

[0282]FIG. 20 is an illustration schematically showing positionalrelationship of the base member 201, the support member 200 of thesecond embodiment and the optical unit 401 described in the firstembodiment. Incidentally, in FIG. 20, the base member 201 and thesupport member 201 are seen from the front side of the rear projector 1.Further, in FIG. 20, in order to clarify the disposition of the basemember 201 and the support member 200, the optical unit 401 issimplified and only the projection lens 46 constituting the optical unit401 is shown in dotted line.

[0283] The base member 201 is constructed by metal plate body, which hasconvex cross section projecting downward.

[0284] Though not illustrated, both end surfaces of the lateral side ofthe base member 201 abut to the base member support projecting from theend surface of the lateral side 132 of the lower cabinet 13 inapproximate normal line direction. In other words, the base member 201is supported by the lateral sides 132 of the lower cabinet 13.

[0285] Further, a first screwing mechanism 210 extending toward theopposing support member 200 is provided on four positions of the endsurface of the convex portion of the base member 201. The first screwingmechanism 210 extends in a direction approximately orthogonal with thereceiver surface 21 of the leg 20. Incidentally, though variousconfigurations are possible for the first screwing mechanism 210, a holepenetrating the convex portion is formed and a nut 210A is fixed to aposition corresponding to the hole by welding etc. in the presentembodiment.

[0286] Further, approximately arc-shaped notch 201A is formed on theedge of the convex portion. When the optical unit body 401A described inthe first embodiment is mounted on the support member 200, theprojection lens 46 of the optical unit body 401A is located at theposition of the notch 201A.

[0287] The surface of the convex portion of the base member 201 isslanted downward toward rear side relative to the surface on bothlateral sides.

[0288] The support member 200 is located on the lower side of the basemember 201, which is provided with an inclination adjuster 203 and arotary position adjuster 204.

[0289] The rotary position adjuster 204 has the rotary member 204A, therotary base member 204 b and the adjusting portion 204C as in the firstembodiment.

[0290] The rotary base member 204B is provided with a second screwingmechanism 220 extending substantially in the same direction as the firstscrewing mechanism 210 of the base member 201 at the positioncorresponding to the rotation guide 204A2 of the rotary member 204A.Incidentally, though various arrangements are possible for the secondscrewing mechanism, the same structure as the first screwing mechanismis employed in the present embodiment.

[0291] In the present embodiment, four pairs of the first screwingmechanism and the second screwing mechanism are provided on apredetermined position of the base member 201 and the rotary base member204B approximately along the normal line of the receiver surface 21 ofthe leg 20.

[0292] Incidentally, the rotary position of the optical unit body 401Ais adjusted by the rotary position adjuster 204 in the same manner asthe first embodiment and detailed description is omitted.

[0293] The inclination adjuster 203 has approximate column shape havingan external thread corresponding to a threaded hole formed on the nut210A of the first screwing mechanism 210 of the base member 201 on afirst end and another external thread corresponding to the threaded holeformed on the nut 220A of the second screwing mechanism 220 on a secondend thereof. The external thread on the first end and the externalthread on the second end are inversely arranged. In the presentembodiment, the external thread on the first end is right-hand threadand the external thread on the second end is left-hand thread.Incidentally, such arrangement is not limited, but the external threadon the first end may be left-hand thread and the external thread on thesecond end may be right-hand thread.

[0294] The first end of the inclination adjuster 203 is screwed to thefirst screwing mechanism 210 of the base member 201 and the second endthereof is screwed to the second screwing mechanism 220 of the rotarybase member 204B. When the inclination adjuster 203 is screwed to thefirst screwing mechanism 210 and the second screwing mechanism 220, theinclination adjuster 203 is inserted to the rotation guide 204A2 of therotary member 204A. At this time, the surface on the convex portion ofthe base member 201 is approximately parallel with the surface of therotary position adjuster 204.

[0295] The rotary knob 203B1 is formed at approximately center of theinclination adjuster 203 as in the first embodiment.

[0296] In order to adjust the inclination position of the optical unitbody 401A mounted on the support member 200, the rotary knob 203 b 1 ofthe inclination adjuster 203 is rotated and the screwing amount of theinclination adjuster 203 with the first screwing mechanism 210 and thesecond screwing mechanism 220 is changed, thus changing the position ofthe rotary position adjuster 204 relative to the base member 201. In thepresent embodiment, when the rotary knob 203B1 is rotated in thedirection of arrow A in FIG. 20, the first end and the second end of theinclination adjuster 203 moves in a direction protruding from the firstscrewing mechanism 210 and the second screwing mechanism 220 relative tothe base member 201 and the rotary position adjuster 204. In otherwords, the relative position between the base member 201 and the rotaryposition adjuster 204 comes close. On the other hand, when the rotaryknob 203B1 is rotated in the direction of arrow B in FIG. 20, therelative position between the base member 201 and the rotary positionadjuster 204 are spaced apart. The operation is conducted on the fourinclination adjusters 203, thus adjusting inclination position of therotary position adjuster 204 and inclination of the optical unit body401A relative to the screen 51 in up-shift direction.

[0297] When the four inclination adjusters 203 are adjusted one by one,the base member 201 is relatively moved toward and away from the rotarybase member 204B at the portion corresponding to the inclinationadjuster 203 to be adjusted relative to the unadjusted three inclinationadjusters 203. In other words, the inclination position of the rotarybase member 204B in up-shift direction relative to the screen 51 isdistorted. In the present embodiment, the load applied on theinclination adjuster 203 in accordance with distortion of the rotarybase member 204B is absorbed by the clearance between the externalthread formed on the first end and the second end of the inclinationadjuster 203 and the internal thread formed on the first screwingmechanism 210 and the second screwing mechanism 220. In the presentembodiment, in order to change the inclination of the optical unit body401A by the inclination adjuster 203, the angle of the rotary basemember 204B is changed within a range of 0.5 to 1.0 degree relative tothe surface of the convex portion of the base member 201.

[0298] The arrangement other than the above-described base member 201and the support member 200 is approximately the same as the firstembodiment and approximately same arrangement as the first embodiment isused for cooling mechanism.

[0299] [2-2. Effect of Second Embodiment]

[0300] According to the above second embodiment, following advantagescan be obtained as well as substantially identical advantages of theabove (1), (2), (4) to (8) and (12) to (20).

[0301] (21) The optical unit 401 and the power source block 300 arelocated between the base member 201 and the rotary position adjuster 204and are isolated in the lower cabinet 13 from the other components suchas the screen 51 by the base member 201 and the rotary position adjuster204. Accordingly, the base member 201 and the rotary position adjuster204 work as a duct for guiding the cooling air in the internal coolingmechanism 500, thereby efficiently cooling the components in the opticalunit 401 and the power source block 300. Further, since the cooling aircirculates along the base member 201 and the rotary position adjuster204, the base member 201 and the rotary position adjuster 204 can alsowork as a component for insulating heat to the screen 51 disposed in theupper cabinet 12.

[0302] (22) Since the surface of the convex portion of the base member201 is slanted relative to the surface on the right and left sides, thesupport member 200 is inclined in advance when being mounted to the basemember 201. Accordingly, by minutely adjusting the rotary knob 203B1 ofthe inclination adjuster 203, the inclination of the optical unit body401A mounted on the support member 200 can be adjusted.

[0303] (23) Since the first screwing mechanism 210 and the secondscrewing mechanism 220 are respectively provided to the base member 201and the rotary base member 204B and the inclination adjuster 203 is acomponent screwed to the first screwing mechanism 210 and the secondscrewing mechanism 220, the base member 201 and the rotary positionadjuster 204 can be connected with a simple structure and theinclination of the rotary position adjuster 204 relative to the basemember 201 can be changed with a simple structure.

[0304] [3. Modification of Embodiments]

[0305] Incidentally, the scope of the present invention is notrestricted to the above-described embodiments, but includesmodifications as shown below.

[0306] For instance, though the support member 200 is constructed bymounting the inclination adjuster 203 and the rotary position adjuster204 on the lateral position adjuster 202 in the first embodiment, sucharrangement is not limiting but the inclination adjuster and the lateralposition adjuster may be mounted on the rotary position adjuster.

[0307] Further, though the inclination adjuster 203 has the leg 203A,the column 203B and the movable metal fitting 203C in the firstembodiment, such arrangement is not limiting. For instance, otherarrangement is possible, where the leg 203A is omitted and two movablemetal fittings 203C are provided, one of the two metal fittings 203Cbeing fixed to the rotary position adjuster 204 and the other beingfixed to the lateral position adjuster 202, external groove is formed onboth ends of the column 203B and the column 203B is screwed to the twomovable metal fittings 203C. According to such arrangement, theinclination position can be adjusted by the inclination adjuster 203with a simple structure without providing the leg 203A.

[0308] Further, the position of the leg 203A and the movable metalfitting 203C may be reversed in the first embodiment. In other words,the leg 203A may be provided on the rotary base member 204B and themovable fitting 203C may be provided on the lateral position adjuster202. The inclination adjuster 203 may be designed in accordance with theshape of the support member 200.

[0309] Though the lateral position adjuster 202, the inclinationadjuster 203 and the rotary position adjuster 204 are used for adjustingthe attitude of the optical unit body 401A in the first embodiment, onlythe inclination adjuster 203 may be independently operated.

[0310] Though the support member 200 has the inclination adjuster 203and the rotary position adjuster 204 in the second embodiment, sucharrangement is not limiting. For instance, the lateral position 202 maybe further provided as in the first embodiment. Further, inclinationposition may only be adjusted by providing the rotary base member 204Band the inclination adjuster 203.

[0311] A component for fixing screwing condition of the inclinationadjuster 203 like the movable metal fitting 203C of the first embodimentmay be provided in the second embodiment. According to such arrangement,the most appropriate inclination position of the optical unit body 401Acan be maintained.

[0312] Though the external thread is formed on both ends of theinclination adjuster 203, such arrangement is not limiting. Forinstance, the external thread may be formed on only one of the two endsand the other end may be freely fitted to the base member 201 or therotary base member 204B.

[0313] Though the cabinet 10 (lower cabinet 13) as a casing and the basemember 201 as the support plate are independently constructed in theabove-described embodiments, the lower side 134, the lateral side 132and the upper side 133 of the cabinet 10 (lower cabinet 13) may be usedas a support plate. In other words, the support member 200 is directlysupported by the lower side 134, the lateral side 132 and the upper side133. According to the above arrangement, the production cost andassembly time of the rear projector 1 can be reduced by omitting thenumber of components.

[0314] Though a rear projector using three optical modulators is takenas an example in the above respective embodiments, the present inventionmay be applied to a rear projector using only one optical modulator, arear projector using two optical modulators and a rear projector usingmore than three optical modulators.

[0315] Though the liquid crystal panel is used as the optical modulator,an optical modulator other than liquid crystal such as a device using amicro-mirror may be used. In such arrangement, the polarization plate onthe light emitting side can be omitted.

[0316] Though transmissive-type optical modulator having differentlight-incident side and the light-emitting side is used in the aboveembodiments, a reflective optical modulator having the samelight-incident side and the light-emitting side may be used.

What is claimed is:
 1. A rear projector, comprising: an image generatorhaving an electric optical device that modulates a light beam irradiatedby a light source and forms an optical image in accordance with imageinformation and a projection optical system that enlarges and projectsthe optical image; a box-shaped casing that houses the image generator;and a screen exposed on one of the lateral sides of the box-shapedcasing onto which the optical image generated by the image generator isprojected, the casing having a support plate that supports the imagegenerator, the image generator being mounted on a support base having asupport surface inclined relative to the support plate, the supportplate being provided with an inclination position adjusting mechanismthat adjusts the inclination position of the image generator relative tothe support plate.
 2. The rear projector according to claim 1, whereinthe support base is disposed on the support plate in an inclined manner.3. The rear projector according to claim 1, wherein the support base isdisposed on the lower side of the support plate in an inclined manner.4. The rear projector according to claim 1, wherein a planar positionadjusting mechanism that adjusts the planar position of the imagegenerator relative to the screen is provided on the support base.
 5. Therear projector according to claim 4, the planar position adjustingmechanism comprising a slide adjuster that adjusts the position of theimage generator in a direction along the screen and in normal linedirection of the screen.
 6. The rear projector according to claim 1,wherein a rotary position adjusting mechanism that adjusts rotaryposition of the image generator relative to the screen is provided onthe support base.
 7. The rear projector according to claim 6, whereinthe rotary position adjusting mechanism adjusts the rotation of theimage generator around planar position of the optical axis of the lightbeam irradiated by the projection optical system.
 8. The rear projectoraccording to claim 1, wherein both of the support plate and the supportbase are provided with a screwing mechanism extending toward theopposing support plate or the support base, and wherein the inclinationposition adjusting mechanism is a screwing component having a first endscrewed to the screwing mechanism of the support plate and a second endscrewed to the screwing mechanism of the support base.
 9. The rearprojector according to claim 1, wherein either one of the support plateor the support base is provided with a screwing mechanism extendingtoward the opposing support plate or the support base, and wherein theinclination position adjusting mechanism is provided with a screwingcomponent having one end screwed to the screwing mechanism provided onone of the support plate and the support base and a convex componentprovided on the other end of the screwing component rotatably fitted toa concave portion formed on the other of the support plate and thesupport base.
 10. A rear projector, comprising: an image generatorhaving an electric optical device that modulates a light beam irradiatedby a light source and forms an optical image in accordance with imageinformation and a projection optical system that enlarges and projectsthe optical image; a box-shaped casing that houses the image generator;a screen exposed on one of the lateral sides of the box-shaped casingonto which the optical image generated by the image generator isprojected; and a reflection optical system that is located on theoptical path of the light beam irradiated by the projection opticalsystem to reflect the light beam toward the screen, the reflectionoptical system being attached to the interior of the casing by a firstholder holding the upper end and the lower end of the reflection opticalsystem, wherein an attitude adjuster that adjusts the position of theoptical axis of the reflection optical system in up-shift directionrelative to the light beam irradiated by the projection optical systemis provided on the first holder on the upper end.
 11. The rear projectoraccording to claim 10, wherein the first holder on the upper end has agroove for an end of the reflection optical system to be inserted, andwherein a gap is formed between the end of the reflection optical systemand the bottom of the groove when the reflection optical system isattached.
 12. The rear projector according to claim 10, furthercomprising an elastic member interposed between a surface of the firstholder and the surface of the reflection optical system opposite to thereflection surface thereof.
 13. The rear projector according to claim10, wherein the reflection optical system is attached to the casing by asecond holder holding the lateral side of the reflection optical system,and wherein an elastic member is interposed between a surface of thesecond holder and the reflection surface of the reflection opticalsystem.